The Face on the Milk Carton, by Caroline B. Cooney

Imagine if you suddenly had reason to believe that the people you called Mom and Dad were not actually your parents. (And what teen hasn't thought that at least once?) That's exactly what happens when Jane Johnson comes face to face with her own picture on the back of a milk carton. Because Cooney's novel was published in 1990, today's readers will likely notice the characters' glaring lack of computers, media, and cell phones as Jane searches for answers. However, it remains a very clever and suspenseful storyline and Jane (who eagerly anticipates driver's training, daydreams about her future children, and constantly tries out more glamorous spellings of her name) will resonate with many female readers.

Cooney, C.B. (1990). The Face on the Milk Carton. New York: Bantam Doubleday. ISBN 0-440-22065-3.